"Young people get caught up in knife crime and gangs in all manner of different ways," she told politics.co.uk.

"We do know that young people spend so much time on the internet - it just seems to me government and the police really need to wake up and tackle it if we're going to get to the root of the problem."

Ms Alexander, whose Lewisham East seat was affected by this summer's London riots, said at present videos can only be removed from YouTube when they are flagged as unsuitable by a sufficient number of people.

"This is clearly a start, but it is not good enough," she said, calling for police to be given have the ability to go through the courts and get access to these websites and videos blocked.

The Home Office said it was difficult for UK authorities to intervene on the internet because of the international nature of the internet.

"The issue is where the content is hosted," a spokesperson explained.

"The police already have powers to remove content if it is hosted in the UK. If it is hosted abroad, police are limited in what they can do. However they can speak to their US counterparts and have them removed."

But Ms Alexander said a minister from the Department for Culture, Media and Sport had indicated interest after the debate.

The DCMS is set to publish a communications bill next year which could update provisions in the Digital Economy Act 2010, which makes it a criminal offence to send "a message or other matter that is grossly offensive or of an indecent, obscene or menacing character".

"It does not provide a means of requiring that the violent material be removed from public view on the internet," Ms Alexander told MPs earlier this week.

"Clearly, we need to go after the gang members themselves, but we also need to be able to remove what is effectively their advertising material."

Civil liberties campaigners could contest proposals which would see the police handed the discretion to remove videos from internet sites, even with judicial approval.

"I would rather take criticism about that than have parents come to me in Catford, in Lewisham, when their children's lives have been utterly devastated by gangs and knife crime," Ms Alexander added.

"These videos are viewed tens of thousands of times... it is completely offensive and I'm totally appalled by what I see. We need to find a way of tackling this really hateful material which is out there on the internet."